786 
MR. BRODIE ON THE CONDITION OF CERTAIN ELEMENTS 
100 parts of this peroxide require 149’7 parts of chloride of silver to one equivalent 
of the oxygen it contains. Hence 3 grms. of the peroxide require 4’491 grms. of the 
chloride for the same proportion. 
In the first four experiments, in which comparatively small quantities of chloride of 
silver, at most not half an equivalent, were taken, the loss increases nearly with the 
mass of the chloride, and bears therefore no constant ratio to the loss from the per- 
oxide. In all these four experiments the chloride has been reduced nearly in the 
same proportion, but yet between the first and second experiment there is a difference 
which is not found between the other three, as may be seen from the following com- 
parison of the chloride of silver taken with the chloride found. 
Exp. 
Chloride of silver taken, jchloride of silver found. 
1. 
100 
53-1 
2. 
100 
39*3 
3. 
100 
40*1 
4. 
100 
39-3 
It appears from this comparison that in the three last of these experiments exactly 
two-fifths of the chloride taken are reduced, and we may regard this limit of reduc- 
tion as the circumstance which here determines the action. The gradual increase of 
loss, with the mass, does not continue, or the increase becomes very small, for one 
and three equivalents of chloride give very nearly the same amount of reduced 
silver, equivalent to exactly one-fourth of the oxygen in the peroxide. There is also a 
constant ratio of loss, which appears likewise to be connected with the increase of 
mass where the ratio is as 7 : 2, and there is one exception to the order of the series 
where the loss does not stand in the same general relation to the mass, which may 
be observed in the other experiments. In this, however, the same simplicity of ratio 
prevails, and it is evidently a term of the series ; the ratio of the loss being as 3:1. 
It is worthy of observation, that the turning-point of the action where the loss ceases 
to increase with the mass, lies at any rate near to that point where the decomposing 
bodies are taken in equal equivalent proportions. 
My experiments had led me to suspect that some circumstance connected with the 
particular preparation of the peroxide employed materially influenced the results. 
This circumstance might be the proportion of free baryta in the peroxide, which was 
not quite the same in different preparations, or it might be some peculiarity in the 
molecular condition of the peroxide itself due to some other cause ; I repeated there- 
fore the experiments made with one peroxide with another preparation, and arranged 
these experiments apart. 
The following experiments were made also with chloride of silver at 100°, but with 
the peroxide Q containing 8'58 per cent, of oxygen. The Tables are of the same 
nature as before. 
rison of these quantities, nearly the same quantity of the peroxide, 3 grms., was, with some few exceptions, 
always employed. The experiments, as will be seen, do not call for any more exact comparison than can thus 
at a glance be made. 
